A new undercover video investigation by a national animal welfare group claims to show disturbing conditions at a Texas farm operated by the country's largest egg producer and distributor.

The Humane Society of the United States says that one of their investigators documented a range of filthy, unsanitary conditions while working at a Cal-Maine Foods operation in Texas over a five-week period this fall. A five-minute video produced by the group shows hens confined in overcrowded cages with rotting corpses, dead and injured birds trapped in cages, eggs covered in feces, and escaped hens floating in manure pits.

"A lot of these conditions seem to be pretty uniform throughout the industry," said Paul Shapiro, the director of the Humane Society's Factory Farm program. "It's not a matter of just a few rotten eggs."

Battery cage systems allow for large-scale egg operators to house tens of thousands of hens in one barn. The Cal-Maine facility in Waelder, Texas includes 18 barns with more than 180,000 cages and 1,000,000 million hens, according to the Humane Society.

The release of the Humane Society video comes on the heels of Cal-Maine's recent recalls of 1.7 million eggs after the Food and Drug Administration notified the company of positive tests for Salmonella Enteritidis, the form of the Salmonella bacteria that sickens humans, at an Ohio company that supplies eggs to Cal-Maine.

In a statement, Cal-Maine Foods said, "All of the company's facilities are operated in full compliance with existing environmental, health and safety laws and regulations and permits." In addition, the company stated that "all of [its] eggs are produced in accordance with United Egg Producers (UEP) animal care guidelines."

Humane Society Videos From Rose Acre and Rembrandt Enterprises

Cal-Maine is the largest egg producer in the U.S., selling approximately 778 million dozen shell eggs last year, roughly 18 percent of the domestic market. The Mississippi-based company is the third major egg producer to be targeted this year in the Humane Society's campaign to expose what the groups calls the "inherent cruelty" in cage confinement of egg-laying hens. The group released videos in April showing similar scenes at operations owned and run by the nation's second and third largest producers -- Rose Acre Farms and Rembrant Enterprises.

At the time, an executive from Rose Acre told an agriculture news service that the company stood by its production practices and would be conducting a third party audit of its Iowa farms.

An egg industry trade group paper aimed at countering the Humane Society campaign argues that cage confinement was originally adopted in the 1940s and 50s as a way to meet growing demand for eggs and improve sanitary conditions. The paper, published by the United Egg Producers, states that "housing hens in cages removed the bird from exposure to its own feces, and eliminated many feces-related parasite problems."

The massive salmonella outbreak over the summer connected to other large-scale produces' operations, which resulted in the recall of over a half-billion eggs, has sparked concerns and questions over conditions at the nation's large-scale egg producers.

The Food and Drug Administration found "significant deficiencies" at the Iowa farms implicated in the massive recall. Agency inspectors found the presence of large piles of manure, fly and rodent infestations, and cited significant problems in the producers efforts to mitigate cross-contamination.

The FDA is still investigating the source and cause of the contamination.

Scientific research shows that a complex set of factors influence the risk of infection from Salmonella Enteritidis. These factors include flock size, the presence of rodents, the age of the facility, cleaning methods between flocks, and vaccination rates of chickens.